Mangawhai beat what probably on paper was the strongest of the sides left in the last eight, that of accomplished Wellington bowler Rob Ashton, 2010 open singles champion Raika Gregory and St Heliers' Barclay Lee, a past runner-up in the open singles.
Ashton, however, mastered the difficult conditions by securing a place in tomorrow's singles final, easily beating one of his arch-rivals on the PBA professional circuit, Waikato's Phillip Bennett, one of the finalists in the pairs.
Ashton will meet a well-performed Aucklander, Graham Growcott, who was also a decisive semifinal winner, over Onehunga's Kevin Dixon.
In tomorrow's women's triples final Anne Bateman, Ann Muir and Lauren Mills, from Whangarei's Kensington club, will defend the title they won last year against Bay of Plenty's Raewyn Willis and Patsy Jorgensen, the winners of the triples in 2008, and their new lead, Robyn Davis.
It will be the second final appearance for Bateman and Muir, as they are also in today's pairs final, though on this occasion in opposition.